LIBRARY 

 NEW YORK 



FORESTRY QUARTERLY "ZZT 



Vol. VII] September, 1909. [No. 3. 



THE WHITE PINE BLISTER RUST. 

 By C. R. Pettis. 



It is very much to be regretted that another disease of a very 

 serious nature has been imported into this country. This time it 

 is a rust, which attacks White Pine. Its most common name is the 

 White Pine Blister Rust (Peridermium strobi Klebahn), called, in 

 Germany, Weymutskiefernblasenrost. It is a member of the 

 order of Uridineae (rust fungi), and like many of that order is 

 heteroecious, i. e. requiring two hosts for its complete develop- 

 ment. This particular rust has the genus Ribes as its second host. 

 The alternate form on the Ribes is called the European Currant 

 &ust (Cronartium ribicola Dietr.) which is most commonly found 

 on black and red currant, more rarely on gooseberry. 



This disease is not indigenous to this country, and this species 

 of Peridermium has not been reported as found in North America 

 until this summer. The Cronartium was originally described in 

 1856 from specimens collected in western Russia, while the Peri- 

 dermium was first described by Klebahn in 1887 as a distinct spe- 

 cies ; but later through inoculation experiments by him and others, 

 they were found to be only different forms of the same disease. 

 The disease has been reported from Belgium, Denmark, Switzer- 

 land, Norway, France, Austria, England, common throughout 

 Germany. Epidemics have occurred in Sweden, and in some 

 localities of Holland it is so prevalent that the culture of White 

 Pine has been abandoned. 



The Cronartium ribicola Dietr. has been reported only twice 

 in this country. In September, 1906, Prof. F. C. Stewart discov- 

 ered it at the Agricultural Experiment Station, Geneva, N. Y., 

 but could not determine how it was introduced. In order to pre- 



orent the disease from becoming established drastic measures were 

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